Many towed or pushed farm implements need to draw electricity from the vehicle connected to the implement to power certain implement functions. These usually include at least power for lights to permit road movement and/or operate in darkness or poor lighting. The electrical connections typically provided on North American tractors and farm implements are sockets and plugs with multiconductor cables providing seven conductor connections. Typically, six of the conductors are dedicated to the implement lights and ground with only one conductor provided for auxiliary (other or non-dedicated) implement power.
The typical North American auxiliary power connection on farm implements is rated at up to 30 A per conductor. However, by the time voltage drop through the wiring and connector terminals is taken into account, only about 10 A can be provided for sustained end use and only about 15 A for peak loads on the implement. Some implement functions can impose an electric load exceeding these limits, particular peak load limits. If the current draw is sufficiently great, even if only for seconds of operation, special cabling and connections must be provided for both the tractor and implement to assure safety and reliability.
There is an International Standard (ISO) 11783 for the latest generation, implement-tractor communication and control coupling that provides for nine separate conductors/channels. Of these, three are dedicated to control of the coupling itself, two are dedicated to data transmission and the remaining four are dedicated to power and ground. Of the latter, one pair is dedicated to providing stable power and ground for electronics and only the remaining pair is dedicated to providing auxiliary power and ground for non-electronic components (e.g. lights, motors, etc.).
The ISO 11783 connection allocates only the one auxiliary conductor pair to supply all non-electronic power needs of the implement, including lights. The auxiliary power conductor pair are again specified for 30 A sustained, which would permit up to about 45 or 50 A peak. With losses, less than that amount of current will be supplied to satisfy the implement's non-electronic power needs. Of course, older equipment and even some new equipment lack these ISO 11783 connections. Moreover, some farm implements currently being sold already generate peak electrical loads of over 50 A. As performance and capacity of implements is constantly being pushed by market demand, it can be expected that more implements will likely exceed the capability of even this latest generation, ISO 11783 connection. Thus, special dedicated heavy capacity electric cables and connectors or at least a separate conventional power supply cable and connector are likely to continue to be required for many farm implements. Whether one or more than one power supply cable is provided all power has to be supplied by the vehicle 18 that is also used to operate the farm implement.
It would be highly desirable to provide farm implements that can be electrically coupled to a farm vehicle with standard electrical connectors designed to supply a relatively low, sustained flow of electric current (e.g. 10 A-15 A) and draw such a relatively low sustained flow from such connectors and yet intermittently supply on the implement, electric currents greater, even many times greater than the magnitude of the sustained flow of electric current from the farm vehicle to satisfy peak electric loads of the implement.